This invention relates to novel fluorinated poly(naphthyl ethers), cured compositions and multilayer electronic circuit articles comprising the same, and methods therefor.
Polymer films and coatings are often used in the electronic industry, especially in multilayer integrated circuit devices, as insulating materials and passivation layers. Polymers having a low dielectric constant .epsilon. are preferred, because components insulated with them can be designed with higher circuit densities and can operate at higher speeds and with less signal broadening. The effect of .epsilon. on the performance of multilayer integrated circuit articles is discussed in "Microelectronics Packaging Handbook," Tummala et al (eds.), pp. 687-692 (van Nostrand Reinhold); Watari et al., U.S. Pat. No. 4,744,007 (1988); and Budde et al., U.S. Pat. No. 4,732,843 (1988).
Polyimide is an insulator of choice for many electronic applications, because of its superior mechanical and thermal properties and its fabricability into thin films and coatings. However, polyimide has a relatively high .epsilon., a limitation accentuated by polyimide's tendency to absorb water (up to 3-4% in humid environments. Water absorption causes .epsilon. to rise, compromising performance. One commercially available polyimide has an .epsilon. of about 3.2 at 0 % relative humidity (% RH), which rises to about 3.8 at 60 % RH. As noted by Denton et al. in J. Electronic Mater. 14(2), 119 (1985), polyimide moisture absorption can also adversely affect performance through increased insulator conductivity, loss of adhesion, or corrosion. Further, some polyimides are susceptible to hydrolysis and/or attack by solvents (often manifested by crazing or cracking upon exposure to a solvent).
It has been proposed, in Mercer, U.S. Pat. No. 4,835,197 (1989), to improve the solvent resistance of polyimide by curing with an acetylene, maleimide, or vinyl terminated curing agent. However, a polyimide so cured would still have the relatively high dielectric constant of polyimides and their tendency to absorb moisture.
For the aforementioned reasons, it is desirable to develop polymers which have superior high temperature properties, outstanding hydrolytic and solvent resistance, low dielectric constant, and low moisture absorption. The polymers of this invention achieve these objectives.